If using a food processor

Put the flour, salt and butter into the food processor and whizz until the mixture looks like fine breadcrumbs.

With the motor still running add cold water, 1 tbsp at a time, until the mixture starts coming together.

If making by hand

Stir the flour and salt together in a bowl. Rub in the butter until the mixture resembles fine breadcrumbs.

Add 1 tbsp of cold water and stir it in with a round bladed knife. Continue adding tablespoons of water and stirring until the mixture starts coming together.

Turn out onto a lightly floured surface and gently knead into a smooth ball.

Weigh and divide in two: you'll need roughly 60 per cent of the pastry for the base and 40 percent for the lid. For example, if the dough weighs 420g then use 250g for the base and 170g for the lid.

Flatten each piece into a disc then wrap in foil or cling film and chill in the fridge for at least 30 minutes.

Put the chopped onion in a saucepan and add enough boiling water from a kettle to more than cover. Season with a little salt and pepper.

Bring up to a boil then turn down the heat and simmer until the onion is soft.

Drain the onion in a sieve over a jug to catch the cooking liquor: it makes a great base for gravy to serve with the pie.

Leave to cool a little.

Put the sausage meat in a bowl and break up with a fork. Add the sage, thyme, onion powder, ¼ tsp of black pepper or you own preferred seasonings.

Add the drained, cooled onion and stir everything together well.

Highly recommended: break off a small piece of the flavoured sausage meat and cook in a frying pan. Taste and adjust the herbs and seasoning if necessary, adding a little salt if you think it needs it.

On a lightly floured surface, roll out the larger piece of pastry into a circle that will come over the edge of your pie plate: remember to take account of the dip in the middle of the plate if it has one.

Place the pastry on the pie plate and gently press down, making sure it goes down into any dip in the middle of the plate.

Holding up the plate in one hand, go around the edge with a knife to trim away any excess.

Roll out the smaller piece of pastry a little bigger than your pie plate and set aside.

Tip: if you have time, it's a good idea to chill the cut-out pastry again. This will help prevent any shrinkage during cooking.

Spread the sausage meat filling evenly all over the pastry bottom, leaving a bare 2 cm border all round.

Brush beaten egg all over the bare border then place the pie lid on top, pressing all around to seal.

Cut off any excess pastry, then go round again pressing down with the tines of a fork or pinch between thumb and index finger for a wavy edge.

If liked, gather and re-roll any leftover scraps of pastry to make decorations for the pie. Stick them on using some of the beaten egg.

Tip: the pie can be chilled in the fridge at this stage and cooked later if liked.

Preheat your oven to 200°C / 180°Fan /Gas 6 /400°F with a shelf in the middle and a large baking tray on it (preheating a tray helps to crisp the bottom of the pie and will also save any fat or juices leaking into your oven).

Brush a layer of beaten egg all over the pie.

Cut a cross, slits, or make holes in the centre to let out steam.

Transfer the pie to the tray in the oven and bake for 20 minutes.

After 20 minutes, reduce the oven temperature to 180°C / 160° Fan /Gas 4 / 350F.

Optional: Take the pie out of the oven and add another layer of beaten egg and return to the oven.

Bake until golden and cooked through: approximately 30 minutes more.

Rest the pie for 5 - 10 minutes before slicing and serving.

Cooked pie will keep in the fridge for 2 - 3 days or can be frozen.

Reheat thoroughly in a moderate oven, microwave or air fryer (you can quickly reheat in a microwave then transfer to the oven or air fryer to re-crisp the pastry).